Process and apparatus for producing filaments



1944- J. J. REIS, JR 2,356,886

PROCESS AND APPARATUS. FOR PRODUCING FILAMENTS Filed Jan. 27, 1942 m Z j '3 69 47 if 3% 21 59 if gwmm @ewzffink Patented Aug. 29, 1944 UNETED PROCESS AND APPARATUS FOR PRODUCING FILAMENTS Joseph J. Reis, Jr., Catonsville, Md., assignor to Pittsburgh County,

Plate Glass Company, Allegheny Pa., a corporation of Pennsylvania 8 Claims.

This invention relates to artificial filaments, yarns 'or strands, and it has particular relation to a process and apparatus designed to produce filaments of tapered form.

One object of the invention is to provide an improved process of tapering an artificial filament as it is formed so as to include a series of successive tapered sections.

Another object of the invention is to provide an improved process of successively tapering filament sections wherein the tapers proceed recurrently in the same direction along the length of the filament.

Another object of the invention is to provide an improved apparatus for manufacturing filaments having tapered sections.

In the manufacture of artificial filaments composed of organic plastics, it is desirable under certain conditions to vary the filament size at regular or irregular intervals in order to produce goods having desired characteristics. Filaments of varying denier, or composed of sections successively tapered, can be formed into yarns either alone or twisted in multiple relation with threads or other artificial filaments or natural filaments or fibers. The filament structures can also be cut along its length at the termination of each tapered portion which is of any length desired. The cut sections can be employed in the manufacture of bristles for brushes or like structures.

Filaments of the type referred to can be formed of organic plastics, such as cellulose acetate, cellulose nitrate or other cellulosic derivatives, for example, cellulose formate, propionate, or butyrate, thiocarbamic or alkoxy-alkacyl esters of cellulose, methyl, ethyl or benZyl cellulose, or the condensation products of cellulose and glycols or other polyhydric alcohols, or artificial or natural resin, such as vinyl acetal, nylon, etc. It applies likewise to filaments or threads of varying or irregular denier produced by the Wet or coagulation method whether having a base of cellulose acetate or other organic derivatives of cellulose, or composed of regenerated cellulose, such as that obtained by appropriate regeneration of viscose, cuprammonium, or nitrocellulose silk.

In the drawing:

Fig. 1 is a diagrammatic fragmentary elevation of apparatus for producing artificial filaments;.

Fig, 2 is a fragmentary view partially in cross section and partially in elevation illustrating cam and valve action applicable in practicing the invention; and Fig. 3 is a fragmentary plan of an artificial filament.

In practicing the invention, artificial filament structure I 0 is drawn by means of conventional driven collectors rotatable at a substantially constant speed. The filament structure is drawn from spinnerets 3 also of conventional form. Each spinneret communicates through a conduit M with a body of spinning solution 'l'l contained in a tank Hi to which the conduit is connected. Pipe lines 20 'and 2| connected at their inner ends to an intervening fiuid reservoir 23 are connected at their outer ends to the tank l9 and a valve box 24, respectively. A suitable pressure gauge 26 is -included in this line between the tank l9 and reservoir 23.

Gaseous fluid, such as air, under pressure is supplied from a known type of pressure generating apparatus, such as a compression pump 30 which communicates through a conduit 3! with the valve box 24. An exhaust pipe 32 having a valve 33 therein communicateswith the atmosphere and with the valve box adjacent the line 2|. A passage 34 extending through the valve box connects at its opposite ends with the line 2| and conduit 3|, and this passage includes spaced valve seats 35 and 36. The valve seat 35 is formed in a chamber 38 leading from the passage 34 to the exhaust pipe 32.

An inlet valve 31 fitting upon the seat 36 controls admission of air from the pump 30 and has connected rigidly thereon a stem 39 which extends outwardly through the box 24. This stem has a compression spring 40 coiled thereabout between the'box and a disk 4| that is secured adjacent the outer end portion of the stem. The spring exerts force tending to maintain the valve 31 in closed position and thereby to arrest and control admission of air through the conduit 3|. The upper end of the valve stem 39 abuts the outer end portion of a lever 33 which is pivoted intermediate its ends upon a pin 5 carried in a stud '46 that is secured on the valve box.

. An exhaust valve 51 seats upon the valve seat 35 and has a stem -|9 passing through the upper side of the valve box in such a position that its outer end abuts the lever 43beyond the side of the pin 45 opposite the stem 39. A spring 50 is coiled about the stem andis confined under compression between the box 24 and a disk 5| mounted on'the outer stem end. This spring presses the stem upwardly against the lever 43 and maintains a roller or follower 54 mounted on the end of the lever. in contact with a cam which is in turn rigidly mounted upon a driven shaft 6| It is to be understood that the spring 50 is larger and stronger than the spring 40 and as the roller follows the contour of the cam to permit pivoting of the lever, in a clockwise direction (Fig. 2), the resistance of the spring 40 is overcome by the spring 50.

The periphery of the cam so upon which the roller bears has arcuate sections 62 merging into inwardly sloping sections 63 and thence in the relatively abrupt sections 64 leading back to one of the outer or arcuate sections 62. While the roller 54 contacts a section 62, the valve 31 is maintained in closed position. The cam is driven in a counterclockwise direction (Fig. 2) and as the roller is forced abruptly down the section 54, the valve 31 is opened abruptly to admit air through the duct, 34 while the exhaust valve 41 is closed equally abruptly. Thus air pressure in the reservoir 23 is built up at a rapid rate. Like pressure is transmitted to the surface of the spinning solution H, which, in the extrusion operation, is thus forced at greater speed through the spinneret although the speed of the collector l I remains constant. The roller 54 then operates on the sloping cam section 63 to close the valve 31 while at the same time opening the valve 41. During a predetermined interval while the roller is riding on the cam section 62, the valves 31 and 41 remain in the relation shown in Fig. 2. Also during this interval, compressed air in the reservoir 23 and the tank l9 bleeds or escapes through one or both of the control valves 21 and 33 which can be regulated as desired.

The speed of rotation of the cam 60 and the rate at which air escapes from the valves 21 and 33 are so co-ordinated that the pressure on the solution I1 is gradually reduced to a desired minimum until the roller 54 again rides down the cam section 64.

Removable plugs 69 screw threaded into the valve box 24 can be removed to provide for proper access to the valve structure, the elements of which can then be mounted as desired. This arrangement also facilitates the formation of the valve seats 35 and 36.

Each collector ll imposes stretching action upon the filament structure as it is extruded. However, during the period of application of greater pressure, a greater amount of the solution will be extruded. Since the collecting rate remains constant there will be a greater volume of extruded solution to be stretched beginning immediately after the abrupt application of pressure, and hence, the size of the filament is then at its maximum. This pressure is gradually relieved through the exhaust valves 21 and 33 and the amount of solution extruded is gradually decreased. correspondingly the size or denier of the filament is gradually decreased. By drawing the filament structure at a constant speed during these operations which recur at specified intervals, the filament denier is regularly varied and the filament structure assumes the contour approximating that illustrated diagrammatically in Fig. 3. Sections of this kind of filament are tapered from their larger base portions to a relatively narrow neck H. The filament can be cut at the location of the necks in order to provide several sections 10 which are adapted to be employed as artificial bristles suitable for manufacture of brushes or for other purposes It is to be understood that cams of different contours can be employed together with proper regulation of the valves to produce filament sections which taper equally in opposite directions.

Although only one form of apparatus has been shown for practicing the process described, it will be apparent to those skilled in the art that the invention is not so limited, but that various changes can be made therein without departing fromthe spirit of the invention or from the scope of the appended claims.

I claim:

1. In a process for the production of artificial filaments from a confined body of spinning solution of organic plastic, the steps which comprise exposing the top surface of the spinning solution to a confined body of gaseous fluid under pressure, drawing a filament at substantially constant speed through a spinnerette from the body of spinning solution, and periodically increasing and reducing pressure pneumatically in the'gaseous fluid upon the top surface of the solution while the filamentsare being drawn therefrom.

2. In a process for the production of artificial filaments from the spinning solution of organic plastic, the steps which comprise confining the body of solution and a body of gaseousfluid within the same inclosure with the gaseous fluid directly in contact with the top surface of the solution, alternately building up pressure in the gaseous fiuid directly upon the top surface of the spinning solution and exhausting gaseous fluid from the body to reduce its pressure to predetermined degree, and extruding filaments from the body of the solution below the top surface thereof through a spinnerette as the gaseous pressure is being built up and reduced on said top surface to impart variation in denier to the filaments.

3. In a process for the production of artificial filaments from-a confined body of spinning solution of organic plastic, the steps which comprise exposing the top surface of the solution directly toa body of gaseous fluid confined under pressure, extruding through a spinnerette the filaments from the body of solution at a location below the level thereof under the action of the gaseous pressure on said solution, abruptly increasing the pressure in the gaseous fluid upon the solution, and then gradually relieving the pressure to predetermined value to impart variation in denier to the filaments as they are being extruded.

4. Apparatus for the production of artificial filaments comprising a spinning jet, 2. container for a solution of organic plastic communicating with said jet, a pressure chamber communicating with said container and having gaseous fluid therein that is exposed directly to the surface of the solution, means for periodically building up and relieving gaseous pressure in said chamber and on said solution to vary the amount of solution extruded through said jet, and means for drawing filaments at substantially constant speed from said jet.

5. Apparatus for the production of artificial filaments comprising a spinneret, a container for spinning solution of organic plastic communicating with said spinneret, a pressure chamber communicating with said container and with a source of gaseous fiuid under pressure, valve means communicating with said chamber and with the source of gaseous fluid under pressure, means for actuating the valve means periodically to admit gaseous fluid under pressure to the pressure'chamber, and means for exhausting gaseous fiuid from the chamber and container in response to actuation of the valve means.

6. Apparatus for the production of artificial filaments comprising a spinneret, means includsaid spinneret to supply the ing a passageway for containing spinning solution or organic plastic communicating with said spinneret and with a sourceof gaseous fluid under pressure. mechanism alternately placing the surface of the solution in communication with said source or fluid under pressure and with the atmosphere, and a reservoir included in said away for storing up fluid under pressure. 7

7. Apparatus for the production of artificial filaments comprising a spinneret, means for collecting filaments from the spinneret, a container adapted to have therein a body oi'spinning solution of organic plastic and communicating with latter with the solution, valve structure having communication with said container, means for connecting said valve structure with a source of air under pres-- sure, valve actuating mean connected to the filaments comprising a spinneret, a containe? valve for admitting abruptly a volume of air 2 under pressure through the valve upon thebcdy of solution, and air exhaust means for bleeding air from the container whereby pressure on the solution is gradually relieved.

8. Apparatus for the production of artificial adapted to have therein a body of spinning solution of organic plastic and communicating with said spinneret to supphr the latter with the solution, valve structure having means establishing communication with said container, means Iorconnecting said valve structure with a source of air under pressure, valve actuating means connected to the valve for admitting abruptly a volume of air under pressure through the valve upon the body of solution, and air exhaust means for bleeding air from said container whereby pressure on the solution is gradually relieved.

JOSWH J. JR. 

